Runner's High article

Things I learned from this article in the New York Times:

1. Endorphins can be described in layman's terms as "the body's home-brewed opiates."
2. Endorphins increase after prolonged exercise, but the molecules are too big to pass the "brain-blood barrier," and may not be the cause of the Runner's High after all.
3. Scientists believe endocannabinoids are responsible, which were first studied in an attempt to understand marijuana's effect on the body.
4. It is possible to breed mice without endocannabinoid receptors, which make them not want to run as much.

Things that make you go hmm...